This proposal is a request to obtain financial support for a one day symposium on "Structural Biology of DNA Repair" to be presented at the American Chemical Society National Meeting in Washington D.C., August 28th - September 01st, 2005. Different DNA repair pathways have evolved to protect the genome from exogenous and endogenous damage since the maintenance of the correct genetic information is crucial for all living organisms. Mutations are the primary cause of hereditary diseases, as well as cancer, and may also be involved in aging. 80 to 90% of all human cancers are ultimately due to DNA damage. This symposium will focus on the advances made in the areas of base excision repair, nucleotide excision repair, mismatch repair, homologous recombination and translesion synthesis by the recently discovered Y-family DNA polymerases. The speakers chosen for this symposium will present the most recent results obtained for the different repair pathways listed above with an emphasis on the advances made towards the structural characterization of the different repair pathways. An overview about the entire field of DNA repair will be presented at the beginning of the meeting. Each of the speakers have international reputations in their areas of expertise and the goal of the symposium will be to bring experts in the field of DNA repair together so that they will be able to educate the scientific community concerning these repair pathways and thereby attract new investigators to the field and to propel this important area of research in new directions. Major questions such as damage recognition and the interaction of multi-protein complexes towards the successful repair of damaged DNA have to be explored and will be an important factor in the development of new chemotherapeutic agents.